Place paper cupcake liners into a muffin pan, and divide the batter evenly among the cupcake liners, pouring only halfway so the batter doesn't overflow. Bake, rotating halfway through, for 25 to 30 minutes. Remove the cupcakes and let cool.

For the icing: In a bowl, beat the mascarpone, icing sugar, cream, and lemon zest together until the mixture is smooth.